Upgrade: Angular 18, Ionic 8, Capacitor 6

Modernizacion completa del frontend:

- Angular 8 -> 18.2.14
- Ionic 4 -> 8.7.17
- Capacitor 6.x (migracion desde Cordova/@ionic-native)
- TypeScript 5.4.5
- Swiper 11 con Web Components API

Cambios principales:
- Migrar NativeStorage a @capacitor/preferences
- Migrar InAppBrowser a @capacitor/browser
- Migrar Camera a @capacitor/camera
- Migrar Geolocation a @capacitor/geolocation
- Migrar StatusBar/SplashScreen a Capacitor
- Migrar Facebook/Google login a plugins Capacitor
- Actualizar lazy loading syntax (Angular 12+)
- Configurar buildOptimizer: false para Ionic 8
- Limpiar package.json de dependencias obsoletas
- Agregar README con guia de instalacion

Co-Authored-By: Claude <noreply@anthropic.com>

src/assets/i18n/en.json

@@ -139,6 +139,7 @@
     "categories_placeholder": "Category 1, Category 2, ...",
     "keywords": "Keywords",
     "keywords_placeholder": "Keyword 1, Keyword 2, ...",
+    "keywords_hint": "Separate keywords with commas",
     "address": "Address",
     "discover": "How did you hear about us?",
     "discover_details": "Please specify how you found out about us",

src/assets/i18n/es.json

@@ -139,6 +139,7 @@
     "categories_placeholder": "Categoria 1, Categoria 2, ...",
     "keywords": "Palabras Clave",
     "keywords_placeholder": "Palabra clave 1, Palabra clave 2, ...",
+    "keywords_hint": "Separa las palabras clave con comas",
     "address": "Dirección",
     "discover": "¿Cómo supiste de nosotros?",
     "discover_details": "Específica como supiste de nosotros",